Electrical control system for burners and control devices therefor



Nov. 18, 1952 F. B. AUBERT 2,618, 3

ELECTRICAL CONTROL SYSTEM FOR BURNERS AND CONTROL DEVICES THEREFOR 10Sheets-Sheet 1 Filed Aprii 2, 1949 INVENTOR. FRED B. AUBERT BY v 'ATTORNEY Nov. 18, 1952 F. B. AUBERT 2,618,323

ELECTRICAL CONTROL SYSTEM FOR BURNERS AND CONTROL DEVICES THEREFOR FiledApril 2, 1949 1o Sheets-Sheet z FIG.3

- INVENTOR. FRED B. AUBERT BY K a ATTCRNEY Nov. 18, 1952 F a AUBERT2,618,323

ELECTRICAL coiqTR'oL SYSTEM FOR BURNERS AND CONTROL DEVICES THEREFORFiled April2, 1949 10 Sheets-Sheet 3 INVENTOR. FRED B. AUBERT W KATTORNEY .Nov. 18, 1952 an. AUBERT ELECTRIQAL CONTROL SYSTEM FOR BURNERSAND "CONTROL DEVICES THEREFOR l0 Sheets-Sheet 4 Filed April 2, 1949lllll INVENTOR. FRED B. AUBERT ATTbRNEY E M h- Nov. 18, 1952 F. B.AUBERT 2,618,323

- ELECTRICAL CONTROL SYSTEM FOR BURNERS AND CONTROL DEVICES THEREFORFiled April 2, 1949 10 Sheets-Sheet 5 FIG-.6

INVENTOR. FRED B. AUBERT IOI IOO

Maw/(- M ATTORNEY x/IOS Nov. 18, 1952 F. B. AUBERT 2,618,323

ELECTRICAL CONTROL SYSTEM FOR BURNERS AND CONTROL DEVICES THEREFOR FiledApril 2, 1949 10 Sheets-Sheet 6 CD 9 LL INVENTOR- FRED B. AUBERT BY M MATTORNEY Nov. 18, 1952 F. B. AUBERT ELECTRICAL CONTROL SYSTEM FORBURNERS AND CONTROL DEVICES THEREFOR l0 Sheets-Sheet 7 Filed April 2.1949 &

INVENTOR. FRED B. AUBERT ATTORNEY Nov. 18, 1952 F. B. AUBERT 2,618,323

ELECTRICAL CONTROL SYSTEM FOR BuRNERs AND CONTROL DEVICES THEREFOR FiledApril 2, 1949 10 Sheets-Sheet 8 INVENTOR. FRED B. AUBERT M KM ATTCRNEYNov. 18, 1952 F. a. AUBERT ELECTRICAL CONTROL SYSTEM FOR BURNERS ANDCONTROL DEVICES THEREFOR Filed April 2, 1949 10 Sheets-Sheet 9 INVENTOR.FRED B AUBERT ATTORNEY Nov. 18, 1952 F. .B. AUBERJ 2,618,323

ELECTRICAL CONTROL SYSTE FOR BURNERS AND CONTROL DEVICES THEREFOR 1OSheets-Sheet 10 Filed April 2, 1949 INVENTOR., FRED B. AUBERT QM LKMATTQBNEY Patented Nov. 18, 1952' Fries;

ELECTR'IICALQCONTROL SYSTEIVI FORBUBJNF ERS ANDLCO'NTROL DEVICESTHEREFOR FredrB. Auber.t',-: Grosse Pointe, -,Mich-.- Ai plibationAprim,1949, Serial No. 85,064

This invention 1 relates to, new and-useful improvements incontrolisystems for liquid fuel burners and. to newandimprovedjcontrolidevices therei'on- Oneof the objects .oiQthis.invention. is to pro--, vide a new and improvedelectriclal controlsystem for liquid fuel burners. in

Another objectlisito. provide,.a, newiand improved burner. controlsystemwhich controls the supply of fuel. and .igniti'dnthereof in responseto-the occurrence or.non-.occurrence of flame in the burner by=anyflameresponsive means capable of completing an electric-circuit "or' blockingcurrent flow through a circuit,

Another object isto.v provide a burner. control systemhaving-electrictiming means operableto initiate supply .offuel tothetburner. and to .energize an electricdgnitionv therefor. andlhaving,a flame. responsive: means operable to. deenergize the timing meanswmdthe. ignition iupon occurrence: of- =fiame, the timing means .beingoperable to deenergize -the system-v inthe event that ,flame does notoccur in the-burner,

Another object'is ,toprovide a burner control system for a :liquidfuehburner having a blower, ignition, and electrically operatedfuelvalve which is operable: to energize the ignition. and blower prior'tothe F'OpBIliHgiOf 'thafuel :valve and which is operable "to cleenergizethe-ignition and stop the supply of fuelto the burneriin the event ofnon-occurrence of flame:

Another object is: to:v provide a burner :control system having aswitch; operating mechanism therein of s new and improved constructionAnother object is;to-provide a, burner control system; having, anovelrelay switch operated safetymechanism controlledin response-to flame inthe burner;

Another object is atoprovideza novel switch op cratingmechanismeincludingr;an electric timer motor; and. a: pivoted zswitch'soperating; member and :1 having a1: novel gear engaging, means"v fortransmission-of (motion :from: thettimeramotor totheswitch.operatingmember;

Another object is to J. provideia burner control system for controllingthe-supplyrof .fuel-Ito a burner and the ignitio1r-=thereoiandincludinga means to shut oft the-supplyofi fuel in -the ievent thatfiamedces not ooocur in the-burnersub'stantially simultaneously-with theemergence of' fuel thereto.

Another object *is to" provide a burner control system having a-novel=timing means *which will operate uniformly-independently of'varyingam-'- bient temperatures "and: fliictuating 'line --voltages.-

42""Cl'aimsr (Cl. 15828) Another object is to provid a burner controrsystem including an electric-timing mechanism whichvvill assume a safetyshut ofi position upon failure of flame in' the-burner either ir'om-astarting or a running-condition;

Anotheriobjectis to provide a' control device of new and improved'constructionfor a burner-con trol system:-

Another obj ect is to provide a control" device for a burner controlsystem-whichisoperable-t0 shut off the supply of fuel to the burner inthe event of failure of .fiametherein;

Another object is to provide-a-controldevice for a burner controlsystemwhich includesa novel safetyswitch mechanism.

Another *object is to ."provide a: controldevice for a'burnertcontrolsystem which is operableto eife'cta supply of fuel: to the burner anditsignition and whichisioperable'to shut off the'supply of fuel totheburnerjin'theevent that flame does not occur thereinwithinapredetermined time.

Anotherobj'ect is to. provide a'burner controldevice having .a noveltiming means: which will operate uniformly ,indep'en'dentlyof; varying;am

' bient temperatures and fluctuating line voltages,

Othero-bjectswill becomeapparent from time to time throughout thespecification andclaims ashereinafter related;

The novelty of this control system. andcontrol device therefor will .befully, and completely described; and. claimed. in the, specification andclaims which follow.

Inv the. accompanying. drawings to be taken .as part ofthisspecificationthere are clearly and fullyillustrated several. embodimentsof this burner control system, in which drawings Figure 1 is adiagrammatic-'view of oneformoi this burner control system.-

2 is -a view more-orless diagrammatic of the-gear engagingmechanism:for-the timing motor and switch structure associated therewith as showninFig. 1;

Fig.- 3 2 is a viewsimilar to Fig. 2 and-showing the gearsfor the;timingjmotorrandswitch mechanism fully engaged;

Fig. 4 is 'aiview of the systemzas1tshown in: Fig, 1 with: the timingmotor :and switclr'mechanism partially op'erated andtprior totheideenergization of the timerimotcr. .byzthaoccurrence of flamer inthe burner;

Fig. 5is a viewtsimilantoiFigrz l and: showslthe flame responsive switchclosedand '1 the switch structure controlled thereby open for deenergiz=ing the-timer motor,

Fig.- 6 'is a partial view of the-system of Fig: 1

ass ts 3 and shows the timer motor and switch operating structuretherefor in the position assumed in the event of flame failure onstarting operation,

Fig. 7 is a partial View of the system of Fig. 1 and shows the positionof the relay safety switch mechanism in the event of flame failure froman operating position.

Fig. 8 is a view of the electric timing motor and switch operatingstructure associated therewith and having a different form of gearengaging mechanism,

Fig. 9 is a view similar to- Fig. 8 and shows the gear actuatingmechanism and the gears in mesh,

Fig. 10 is a view of the switch operating member of the system of Fig. 1and having a rack and pinion arrangement for transfer of motion from theelectric timing motor,

Fig. 11 is a view similar to Fig. 10 but with the rack and pinion inengagement,

Fig. 12 is a view of the system shown in Fig. 1 but having a planetarygear mechanism for transmitting movement from the electric timing motorto the switch operating member,

Fig. 13 is a view of a modified system similar to that shown in Fig. lbut including a photoelectric tube and circuit therefor for flameresponse and a flow responsive switch which cooperate to deenergize thesystem in the event that flame does not occur in the burnersubstantially simultaneously with the emergence of fuel thereinto, and

Fig. 14 is a diagrammatic view of another modification of this controlsystem.

Referring to the drawings by characters of reference there is shown inFig. l a burner control system having a liquid fuel burner generallydesignated as There is an electrically operated blower 2 driven by amotor 3 which also operates a fuel pump 4 for supplying fuel to theburner nozzle 5. There is an electrically operated valve 6 whichcontrols the supply of fuel to the burner and an electric ignition meansI is provided for ignition of fuel. A room thermostat generallydesignated as 8 controls the energization of the system in accordancewith the heat'requirements of the spac being heated by the burner I.There is a transformer 9 which supplies electric power for energizingthis system and which has the primary I!) connected by lead wires H andI2 to a power source IS. The secondary M of the transformer 9 isconnected by a conductor |5 to the blade l6 and movable contact I! ofthe thermostat 8. The fixed contact l3 of the thermostat 8 is connectedby a conductor 19 to one contact 20 of a reset switch 2|. The othercontact 22 of the switch 2| is connected by conductors 23 and 24 to anelectric timing motor 25. The timing motor 25 is connected by aconductor 26 to another switch which will be described hereinafter andthence back to the other side of the transformer secondary M. The motor25 has a motor shaft 2'! with a pinion gear 28 thereon. There is apivoted member 29 which is pivoted on the motor shaft 2'! and which hassecured thereon two gears 30 and 3| which are operable to transmitmovement from the motor 25 and which are pivotally movable by thepivoted member 29. There is a switch operating member 32 which ispivoted as at 33 and which has a switch operating cam face 34 at itsupper end and a sector gear portion 35 at its lower end. The pivotedmember 29 is operable upon movement to move the gear 3| into or out ofengagement with the sector gear 35 for transmission of motion from themotor 25 to the switch operating member 32. The pivoted member 29 has anextension 36 thereon and a pin 37 protruding therefrom which isengageable with an operating lever 38 for actuation. The lever 38 ispivoted as at 39 and has a leaf spring portion 4E] which engages the pin31 on the gear operating member 29 for resilient operation thereof aswill be subsequently described.

The lever 38 has a magnetic armature portion 4| which is cooperable withan electromagnet 42 for moving the gears into engagement. There is aswitch structure generally designated as 43 which is operated by theswitch operating member 32 and which includes an operating lever 44pivoted as at 45. The end portion 46 of the switch operating lever 44 isof an electrical conducting material and has an arm 41 which functionsas an electric contact. There are a pair of electrical contacts 48 and49 which are carried by a flexible arm 50. There is another electricalcontact 5| which is carried by a flexible arm 52 and limited in itsmovement by a stop member 53. The switch operating lever 44 upon pivotalmovement is first operable to make contact between the contact portion41 and the contact 48 and upon subsequent movement to flex the contactarm 50 to make contact between the contacts 49 and 5|. The end portion54 of the switch operating lever 44 has a downturned portion 55 with abearing roller 56 carried thereon for engagement with the switchoperating cam face 34. The pivoted switch operating member 32 is held bya spring 51 in an initial position out of operating engagement with thebearing roller 56. A spring 58 holds the lever 44 in an initial positionwith the contacts as shown in Fig. 1. There is a stop member 59 whichlimits movement of the pivoted switch operating member 32. There isanother switch structure generally designated as 60 which is in thenature of a double pole double throw switch. The switch 60 has two fixedcontacts 6| and 62 and has a first pair of movable contact arms 63 and64 and a second pair of movable contact arms 65 and 56. The contact arm63 carries two oppositely facing contacts 61 and 68. The contact arm 53is positioned for initial engagement of the contact 31 with contact 6|and the contact arm 65 carries thereon a contact 69 which is initiallyengaged with contact 6B. The contact arm 64 carries oppositely facingcontacts 10 and 1| and the arm 66 carries a contact 12. The contact arms64 and 66 are positioned so that contacts 62 and 10 and contacts H and12 are initially engaged. Contact arms 63 and 64 are arranged formovement together as by a connecting linkage l3 and contact arms 65 and66 are similarly connected by a linkage 14. There is an electromagnet orrelay coil 15 which is coo-perable with an armature portion 16 on thecontact arm 64 for actuating the switch structure 60. There is a latchmember 17 which is urged by a spring 18 toward latching engagement withthe contact arm 66 and which is held out of engagement therewith by theupper prong or arm 19 of the switch operating lever 44. There is a resetmember which is engageable with the arm 19 of the switch lever 44 andwhich has arms 8| and 82 which are engageable with the switch blades 50and 20 respectively. The conductor 26 from the timer motor 25 isconnected to the fixed contact 62 of the switch mechanism 60, thecircuit being completed therefrom back to the transformer secondary l4by the conductor 83 from the switch contact arm 66 and by conductor 84which is connected to the transformer secondary l4. Conductors 85 and 86connect the electromagnet seen-e 42 4:0 conductors 23 andaflrespectively to estab' lis'h a circuit for the-electromagnet' 4221a:parall'el wi'th th'e motor -25; From the conductc'vr I 2 on-thehighvoltage-or primary 'side ot the transformer -9 a. conductor 81 1leads-to the blade or contact arm- 50?. of theswitch 439 The upperarm- 79 ofthe switch-43 iscon ne'cted by a flexible. blade or conductor 88;? andbyar -conductor 89 1to the contact arm' 95 of th'elswitchmech'anism-fifl'z mechanismlfifl a conductor90 leads to the motori 3 ofthe blower 2; this motorbeing connected by conductors 9| and 92 to theotherih'igh voltage' conductor. II .on the primary-side of-the 'transeformer. The fixed contact! 6t of? the switch: mechanism L BIL isconnectedxby conductor 93 toone side of the primary".9diaofiiithe-ignitiorrtrans former 95 :..the other side 'of whi'ch is connectedtozconductor 92 leading backs.toithestransformer;

primaryr The ignition transformer 95rhas a secondary. 96 which isconnectedaby= conductors .91'

and; 93 to the ignition means orr electrodes 1. From the secondaryv I laot the transformer-.9 the conductor 99 zleads \t'O the. fixedtzcontact;I 9920f. a thermostatic stack switch. IIlI, Th'e1.movable contact I02of. thestack,switchclolvis connected by; a-conductor I03' to onewsideoftheurelayscoil: 15:1. The other. side of.-the 'relay. coilisconnectedby., a conductor. I04 .to: :theamovable conta'ctarm 64- of the switchmechanism .99,\th e relay coil circuit being; completedabyt conductors.83 and, 84 back to, the transformer-secondaryI4: The flexible. switcharmjzof theswitch 43-;is con'-. nected by, a conductor I95; tor the.fuel valve 6 which; is in turn connected,v to :high; voltage IconductorII ofrthe transformer9'zbyaareturnconductor I08. Thislast-mentionedcircuit-through the fuel valve B-is in parallel with thecircuits to, the, blower, motorq3gand, the; ignitionjtransformer 95.

In operationthis system,functionsgenerally as follows; Upon a demandforiheatbyrthe space WhiCh =iS heated bywthe burner l theccontactsgl'land Ifl'of the room thermostat 8:a re,closed by awarping of th'e.thermostat blade I6'. The:c1osingfif the room thermostatcontactsestablishes circuitsto the timer motor 25 :and, thevrelay coil42;; From the transformer secondary: Matheycir cuit to-the timer motor25 extendsbywawof conductor I9, thermostatic contacts ll and ;'l8,z

ondu t r: 9 0 t ct nds z; i ue-sw tch !;9J dfi10n 0 O ?Z4wt0onQ o hmqtorfi; From the other side 1 of -thegmotqr, 25 ;con ductor 29- leadstoI the fixed contact 62 of the switch structure ISO and the circuit iscompleted through the closed contacts 92, 10, II and," and-the switchcontact arm 66;to the conductors 83 and 94 which connectback to thetransformer secondary MI- The circuit 'for electromagnet 42 is con-,

38 =is transmitted by the leaf-spring 40 thereon to xthev pin portion3'1 (m th'e pivoted member 29:.and if the. gear teeth of th'eLge'ar-s 9Iand '35' shouldabuti rather than mesh; as is; shown in Fromnthe contactarm 63 of: the'switch Eig'. -2-, the-"leat spring 49 is fle'xedawayifrom th' lever =38 -and is-operable::-to continue-the move ment ofthe pivoted gearengagingmember -29 upon motion ot the gear teeth from:an abutting position so -that they mayassume a meshed position shown-Fig-. 3.1 Upon meshing engagementi'of the-gear: 34 I and the-sector gear35 themovement oflthe tiinermotor-25 is transmitted to the switch loperatingmember 3 Zeiwhich 1 begins: te -pivot to move the camiace 34under the =bearing roller-56 ofthe switch: lever t I- for operationofthe switc'hlever- 44 -andthe switch structure 43; As the-cam face 34 of-the pivoted member 32' begins=to move-milder the bearing ro1ler =58 theswitchlevenfl movesand first :makes cor-itact between the contact armportionll 'and the contact 48 This contaot b'etween the contacts 41 and48 establishes "high voltage :circuits to the blower motor-land th'eignition trans former 95.- Upon continued movement of the cam fa ca 34under the bearingrolIer EB -the swi-t'chlever I I is'moved'further andthe contact arm 50% is fiexed- 'downward thereby until contact ismadebetween the switch contacts 49: and -5l which completes a: circuitfor: energization of the: fuel valve y 6. By this arrangement, thesequential engagement-of the-switch contacts 4! and 48 and 49 and 5|;there is provided-arsimple means for energizing :the blower' and theburner ignition a short predetermined-- time lprior to the openingv ofthe fuel valvep Theadvantages of energizing the'burneni'gnition andblower-a short time prior to the supplying of iuel tothe burner are:well known in the art; the principal advantages being the protectionagainst extinguishment of'the igniti-on arcwhen the line-current hasdropped as a result' of ai=circuit over1oad and also the preventing ofcarbonization on the burner nozzle; This sequential operation of theblower and ignition and fuelvalve has been accomplished. in the pastby'useof:- a current surge relay-switch but by the present construction:the requirement of such: an additional relay switch is eliminated by theuse of an extra switch (contacts 49 and .5 I operated by the main timermotor. The system with the'timer mot-or energized; gears engaged, andoperating member moved toclose the blowerandignition, and fuel valveswitches is showninF-ig; 4; At this-point in the operation-the highvoltage ignition: and blower motor circuits are completed asfollovvs:From the high voltage wirev I2-- the conductor 8'! leads to the contactarm-50- cfthe switch structure 43. From this point the circuitrunsthrough th'e'clo-sed contacts 4'Iand 48, the flexible arm 88, andthe-conductor89 to the switch contact'arm of the switch structure 692 Atthis pointthe blower motor andignition circuits divide, the blower motorcircuitrunning through the switch contacts 68: and -69-and -the.-contact arm 63 andthe ignition circuit running-through" all of theclosed contacts "99, 68; 61; and-6|; The blower motor circuit iscompleted 'by the conductor 90.which connects the switch contact arm 63to one side-of the motor'3 and the-conductors 1 91 and 92 whichlead fromtheother side of the motor to-thehighivoltagewire II. The-ignitioncircuit; is completed from the switch structure 69 by the conductor :93which vconnects the: fixed contact 9| to one sideof the ignitiontransformerprimary 94;: the conductor: 92 connecting the othertside ofthe primary 94 to the high voltage wire I'll At this point in theoperation; the blower 2 is energized and: supplyingair to the burner;the ignition I "is energized for'igniting fuel, and: the: fuel valve: 6is: open permitting: the

fuel pump 4 to supply fuel to the burner. If the fuel is ignited in theburner in the position thus far described and shown in Fig. 4, thethermostatic stack switch IOI will respond to the occurrence of flameand its switch contacts I and I02 will be closed thereby. Upon closingof the stack switch contacts a low voltage circuit is completed from thetransformer secondary I4 by way of the conductor 99, the switch contactsI00 and I02, and the conductor I03 to one side of the relay coil I5. Theother side of the relay coil 75 is connected by the conductor I04 to thecontact arm 64 and the circuit extends through the closed switchcontacts 'II and I2 and the conductors 83 and 64 back to the transformersecondary I I. As is seen by reference to Fig. 4, when the switch lever44 is moved to close the blower and ignition and fuel valve switches theupper arm portion I9 thereof is moved out of engagement with the latchmember 11 and this latch member thereupon moved into a partialengagement with the lower switch contact arm 66. When the stack switchIOI is energized by occurrence of flame and the circuit completed forthe relay coil I5, as was previously described, the relay coil 75 isoperable to attract the armature portion I6 and pull down the contactarms 63 and 64. Upon downward movement of the contact arms 63 and 6d thecontacts 6! and III are moved away from the fixed contacts El and 62respectively but the contacts 68 and II remain closed against theirrespective contacts 69 and I2 as the contact arms 65 and 66 are operableto be flexed or moved upon movement of the arms 63 and 64. Upon openingof the contacts 6| and 67 the circuit to the ignition transformer 95 isbroken and the ignition deenergized thereby. Upon opening of thecontacts 62 and I0 the circuit for the timer motor 25 is deenergized andthe motor is then stopped in the position indicated in Fig. 5. When therelay coil I is energized and the contact arms pulled down as indicatedthe lower contact arm 66 is operable to move into a latching engagementwith the latch member I? as is indicated in Fig. 5 so that upondeenergization of the relay coil the return movement of the contact arms65 and 66 will be restrained and the contact arms 63 and 64 will returnto their original position thus opening the contacts 68 and II from thecontacts 69 and I2 respectively.

From the foregoing description it is seen that there is herein provideda system for the control of a liquid fuel burner which is operable toenergize the blower and ignition in advance of the supply of fuel to theburner and which is operable upon occurrence of flame in the burner todeenergize the ignition circuit and the circuit to the timing motor.Since the circuit for the gear engaging electromagnet 42 is in parallelwith the motor circuit and since it does not extend through any of theswitch contacts which are controlled by the relay coil 15 it is seenthat the gears are engaged upon energization of the electromagnetcircuit by the closing of the room thermostat contacts and not affectedby the operation of the relay switch structure 65 upon occurrence offlame. If, at the start of the burner heating cycle, the flame does notcome on in the burner within the predetermined time required for theoperating member 32 to be moved by the timer motor 25 across the fulllength of the cam face 34, the relay coil 15 will not be energized andthe timer motor 25 will continue to move the switch. operating member.Upon continued movement of the 8 switch operating member 32 by the timermotor 25 beyond the predetermined time required to move the cam face 34under the bearing roller 56 the cam face 34 will move completely outfrom under the bearing roller 56 and the switch lever 44 will then pivotin the opposite direction to open the switch contacts 41, 48, 49 and 5|and will assume the position indicated in Fig. 6. The timer motor willby this time have moved the switch operating member 32 against the stopor limit 50 and will then stall. In normal operation of the system whenthe circuit through the room thermostat 8 is opened the gear engagingelectromagnet #52 is deenergized and the gears SI and 35 disengaged topermit the spring 51 to move the switch operating member 32 back to itsinitial position. However, when the operating member 32 has moved to thesafety position indicated in Fig. 6 upon non-occurrence of flame, thebearing roller 56 and downturned portion 55 of the switch lever 24 willengage the side of the operating member 32 as a latch to prevent it fromreturning to its initial position. When the burner system has operatedthrough to the safety position as in Fig. 6 as a result ofnon-occurrence of flame in the burner the reset member 85 must beoperated to permit the system to be restarted. When the reset member 89is pushed down against the end portion I9 of the lever id, the bearingroller 56 and downturned portion 55 are manually moved out of latchingengagement with the edge of the switch operating member 32 to permitsaid operating member to return to its original position as indicated inFig. l. The finger SI on the reset member 86 is operable to engage theswitch arm or blade 50 to move the contact 48 away from the levercontact surface t! so that the system can not operate in the event thatthe reset member 86 is jammed down. The other finger 82 on the resetmember is operable to open the reset switch 2I simultaneously with themoving of the switch lever 44 out of latching engagement with theoperating member 32. The opening of the reset switch 2| by the resetmember 80 is operable to open the circuit to the gear engagingelectromagnet 22 to disengage the gears to permit the operating member32 to assume its original position as soon as'the lever portions 55 and55 are moved out of latching engagement therewith. If, during theoperation of thesystem, when the system has assumed the positionindicated in Fig. 5 with the blower and fuel valve energized and theignition deenergized and the relay switch 66 in an actuated position,there should be a loss of flame in the burner so that the stack switchcontacts I00 and I02 are opened. the relay coil I5 would be deenergizedand the contact arms 63 and 64 moved upward to their initial position.However, since the contact arms 65 and 66 are latched in a down positionthe movement of the arms 63 and 64 upward would break the contacts 68and II away from the contacts 69 and 12 respectively. The opening of thecontacts 68 and 69 would break the circuit to both the ignition and theblower. The opening of the contacts II and I2 would open the circuit tothe relay coil 75 and maintain open the aforementioned circuit to thetimer motor 25. This position is indicated in Fig. 7 and at this pointin the operation the timer motor 25 and the relay coil I5 cannot againbe operated until the latch member II is released. From this positionthe system can be restarted by opening the-room thermostat cifciiit todeen'ergize the gear enga'ging el'eotroniag'net and permit the switchoperating member 32 to-move back to its original position. When theswitch Operating member '32 is fnoved b'ac'k to its original .positionth'e switch -levr4'4 is pivoted in a s'witch opening direction and th'eupper arm "it thereof is operable to engagef-the latch m'ember "I? andpivot -the same out of latchin'g engagement with the conta'ct arm 66 topermit theamis *6'5 and 66 to return to their original position asshow'n in Figfil.

Fro'm thefolegoil'ig desoription it is seen' -that there is provided -anovel system whereby the ignition and burner and fuel-supply are turnedon initially andif there beflamewithin-a prm determined time theignitionis deener'gized and the timing moto-r stopped, blit if "fiame"does not occur within the said' pr'edeter'min'ed time the timingine'ans is oper alale t'o niov'e the ignition and blower andf-iielva1veswitches to a safety position deenerg'iZin'g -a11 of thecircuits "thereof and -rqui'ring a manual 're'set. There is alsoprovided 3, means -'for locking out the system in a safety position uponfail-ure f -fiarne from a running or operating 'po's'ition. In 'pri'orburner control systems of this general *type one of the principaldisadvantages has been that "unfavorable conditions may result 'fr'om'-'a chattering or -momentary making and breaking of the contac't's orthe various 'swithes in the system. By the arrangement used in thissystem if 'there is-achattering of contacts any place in' the system orany place i in the circuits associated therewith, including'the powersource,the'system'will either go back to its initial starting positionor will assume one of the safety positions indicated according to whichcontacts 'are so chattering. In commercial construction the entiresystem shown with the exception of theroom' thermostat, the stackswitch, the ignition transformer, the blower motor; and the fu'el valvewould probably be enclosed "in a basing as a unitary control device.

Referring to Figs. '8 and 9 there is shown "a slight modification 0f"the gear engaging -meoh anism Y for the 5 timing 'motorof the systemshown in Fig. 1. -nl1 parts which a'recornmonto Fig. 1 are given thesame reference characters. In the gearengaging mechanism of Fig.8 theleve'r'tii of Fig. 1 has substitutedtherefora'linkageinechanism 33 Thelinkage mechanism 3-8 'comprises two links 9 and 4 0 -which are pivotedto each other as at t I The link w -'is pivoted on the pivot- 33 of theopera'ting member 32 and the link "48 is pivoted to the projectingportion BB'off'thege-ar engaging-member was-at42 The link "3'9 has anarmature portionM as'does the lever-membertt in Fig. land is connectedto 'thelever 'me'mber i i 'bya spring -58. The-linkage 38* as" shown inFigQ'S 'is in abent position and has moved the-gears to adisengagedposition. Upon energi'zation of the electromagnet '42 the'armatnreportiomM is attracted thereto and the links B S an'd '4 0 arestraightened to assume the position-shown ilfFig, "9. Upon straighteningof the'links 3'5 and flii the linkage "3S3? is operable to pivot themember "29 to engage the gearsSI and "35 for operation. When'the linkage38 is straightened and the gearsare engaged as shown in 'Fig. 9 thestraightened linkage is operable to receive and restrain thereactive-thrust of the gear? I' against the'sector. gear Referring toFigs. 10 and 11 there 'is shown wherein a "rack-and pinion arrangementis used. The system is otherwise :as shown in I Fig. l.

InFig. 1-0 the lower end "portion 35 of the switch operating member 32is .pivotally connected as :at '10! to a rack member generallydesignatedas I08. The rack'member'lns has'an upper rack portion I09 anda slot I I0 inthe side Wall thereof. There is a pin III whichfits theslot 'I'I9 'slid'ably and along which the member IGBmay have movement.The'rackportion we of the member IE8 is engagable with the pinion gear28 of the timer motor 25 (of which only the gear' 2 8 is shown) and hasa normal initial position but of engagement therewith. There is a member-I I? which extends transversely to the member I03 and which isconnected thereto by the pin WI. The member IIZ has upper'and lowerslots 'I' I3 and Ilfl in which are 'slidably seated pin members 'I I5and 'I I6 respectively. The upperslot H3 has'a laterally projecting slotportion I'H providing a shoulder 'I I8. The-memher 'I' I 2 has alat'er'allv proj ectingarmportion 'I I '9 to which is pivotallyconnected a link member I20 as at i2I. The member II 2 is operable tohave-longitudinal movement of the slots H4 and II3'a10ng the pins H6 andH5 respectively and when moved to a down position is operable to pivotso that the :pin =I I5 is positioned in the lateral slotpoi'tio'n N! "asindicated in Fig. '11. There is a spring In which is connected to thelateral arm II!) as at I23 and which urges'the member I I 2tohave'themovement just described for engaging 'the rack I89 with thepinion gear 23. The'link IZQ -has at-its upper enda laterallyprojectingipin member I'24'which slidably fits and seats againstthe'botto'm end of a'lost motion slot I25 on the end portion I 26 of "alever member I21. There'is'a spring I28 attached to'the lever I2? andwhich pulls it upward against the pin I'Zd'and the linkage I23 to holdthe'member II2 and'therackmember'mfi in the disengaged'positionindicated in Fig. -10, the spring I28 being sli htly "stronger than thespring I22. The lever I21 has an armaturelpo'rtion 4 I, as does'thelever 38 inFig. l, -which"is"cooperable with the electromagnet 12 'foroperating the gear mechanism herein described. There is areset'levermember I29 which is pivoted at IGI) and which isengageable withthe'pin'I 24 "0n'th'e'link I2'0 for moving thesarne. The lever'mernber I29 ispivotally connected a's atI3I to a thrust member I 32 which is arrangedfor operation by theresetmember 8t.

In operation this gear engaging mechanism functions as foll'ows When theelectromag'net i2 is energized and attracts the armature-portion 4| thelever 'IZIis pulled downward permitting the link I2Il'to move andthe'spring I22 to operate and pivot the'me'mber I' I Zto 'en'gag'e therack I 99 withthe-pinion gear-2 3 as-indicated-in Fig'll. When 'themember 'II2 is pivoted as indicated in Fi'g.;1=-1, the-pin H5 ise'ngageable with the shoulder II-B of the lateralslot-portion I I1andi'soperable to resist the reactive'thrustof the motor 25throug'h'thepinion gear 2 8 against the rack I 09. If the pinion gearand rack teeth abut rather than mesh upon downwardmovement oftheleverl2l,'the lever I21 will move -thro-ugh'to its down position'as in Fig.l1 but the s'lot i2 3-will have lost motion relative to thepin I -2 iand thespring I22 will subsequently'cause these gearteethtobe enmeshed.By the arrangement of springs I22 and i228 'asshown herein therelayfihas only-to operate against Y the differential of force "between them Ifthe timing'motor-moves the rack-and operating "member through'tO-alO'Ck6d-0llt position similar to that shown in Fig. 6 the resetmember 80 upon actuation is operable to move the link I32 to manuallydisengage the rack I69 from the pinion gear 28 so that the necessity forthe reset switch 2I is eliminated when this type of gear engagingmechanism is used with the system of Fig. 1.

In the form of the invention shown in Fig. 12 the system issubstantially identical to that of Fig. 1 except that the switchoperating member 32 is operated by a planetary gear mechanism. The timermotor has a pinion gear 28 on its shaft which functions as the sun gearof a planetary gear mechanism generally designated as I 33. Comprisingthe planetary gear structure I33 are the sun gear 29, the planet gearI34 and the internal or drum gear I35. The operating member 32 ispivoted on the shaft 21 of the motor 25 and is pinned to the planet gearI34 as at I36. There is a strip or wire I31 which is looped around the Fdrum gear I35 and which is operable as a brake therefor. The wire I31 issecured at one end as at I38 and is connected at its other end to oneend of a lever I39 as at I40. The lever I39 is urged by a spring I 4|toward a brake-loosened position and has an armature portion I42 whichis cooperable with the electromagnet 42. The spring 51 which isconnected to the operating member 32 is operable to hold the member 32in a switch opened position as in 'Fig. 1.

The operation of this system is the same as that shown and described forFig. 1 with the exception that the electromagnet 42 when energizedinstead of moving gears into engagement is operable to tighten the brakeI31 for the drum gear I35 and thus to cause the motor to transmitpivotal movement to the operating member 32 through the sun gear 23 andthe planet gear I34.

Referring to Fig. 13 there is shown a burner control system which isidentical in all respects to that of Fig. 1 with the exception that aphotoelectric circuit and a flow responsive switch arrangement areprovided for controlling the energization of the relay coil 15 in placeof the stack switch IIJI in Fig. 1.' The system of Fig. 13 functionsgenerally the same as that of Fig. 1 in that upon closing of the roomthermostat the timer motorisenergized and the gear train pulled in totransmit movement to the pivoted operating member and the switchescontrolled thereby. It should be noted that any of the alternate formsof gear engaging mechanism as are shown in Figs. 8, 10 and 12 could beused in this system in the manner described for the system shown inFig. 1. In this system the conductors 99 and I03 which are in thecircuit to the relay coil 15 are controlled by the open contacts I43 andI44 of a relay switch generally designated as I45. The contact I43 iscarried by a movable lever arm I46'having a magnetic armature I41 andheld by a spring I48 in an initially open position. There is a relaycoil I49 which is operable upon energization to attract the armature I41and close the contacts I43 and I44 to complete the circuit forenergizing the relay coil 15. There is provided a transformer I50 havinga primary I5I and a pair of secondary portions I52 and I53. There isalso provided an electron tube I54 having a cathode I55, cathode heaterI56, screen grid I51, control grid I58 and an anode I59. A pair ofconductors 1'60 and I6I connect the cathode heater I56 to thetransformer secondary portion I52. The cathode I is connected by aconductor I 62 to the cathode heater'wire I6I as at I63 which is in turnconnected by a conductor I 64 to the screen grid I51. The transformer sconda y Portion I53 is connected'to one side of the secondary portionI52 as at I65 and at its other end is connected by the conductor I66 toone side of the relay coil I49. There is a conductor I61 and resistorI68 in series and connecting the other side of the relay coil I49 to theanode I59 of the electron tube I54. A condenser I69 is connected acrossthe relay I49 as at I10 and I11 and is operable to even out thepulsations of electric current supplied by the electron tube I54. Theconductor I 61 leading to the electron tube anode is also connected toone side of a condenser I12, the other side of which is connected toground at I13. The control grid I58 of the electron tube I54 isconnected by a conductor I14 and a resistor I15 to the cathode I16 ofthe photoelectric cell I11. The anode I18 of the photocell I 11 isconnected to ground as at I19. The photocell I11 is positioned adjacentthe burner to respond to the occurrence of flame therein and is operableto transmit its response to flame instantaneously to the electron tubeI54. There is provided another circuit for controlling the energizationof the relay coil 15 which is in parallel with the circuit controlled bythe photocell I11 and which comprises two conductors I and IN leadingfrom the conductors I03 and 96 respec tively to the open contacts I82and I83 of a flow or pressure responsive switch mechanism generallydesignated as I84. The fiow or pressure switch I64 and actuatingmechanism therefor is shown diagrammatically and any suitable flow orpressure responsive mechanism would serve the purpose. Thegeneral-requirement of this flow or pressure responsive switch is a flowresponsive or pressure responsive means I65 in the fuel line to theburner operable in response to flow of fuel or to fuel line pressure tomove to a switch actuating member I66. The switch actuating member I86has a cam portion I81 thereon which is operable to move the arm I88carrying the contact I82 to close the contacts I82 and I63 momentarilyand then upon either continued or reverse movement to permit thesecontacts to open. The flow characteristics of the flow or pressureswitch I84 are such that the contacts I82 and I83 will be closed uponinitiation of fuel flow or fuel pressure indicating fuel flow to theburner and will be reopened a momentary period later by which time fuelwill normally have emerged into the burner.

In operation this control system functions as follows: Upon closing theroom thermostat 8 the timer motor 25 is energized and the gears areengaged by energization of the electromagnct as was described for thesystem shown in Fig. 1. Similarly, as the operating member 32 is pivotedand the switch lever 44 moved, the contacts 41 and 48 are first made toenergize the blower motor 3 and the ignition 1 and subsequently thecontacts 49 and 5I are closed to energize the fuel valve 6. As wasdescribed for Fig. 1 when the relay coil 15 is energized and the switchmechanism 66 pulled in the switch contacts 61 and 10 are broken awayfrom the contacts 6| and 62 respectively to deenergize the ignition andthe timer motor. Also, upon deenergization of the relay coil 15subsequent to energization thereof the latch member 11 is operable torestrain the return movement of the switch contact arms 65 and 66 sothat the contacts 68 and H are moved away from the contacts 59 and 12respectively to deenergize the system and cause it to assume a safetyposition. Likewise the release of the switch lever 44 is operable tomove the latch member 11 to permit the switch contact arms 65 and 66 toreturn to their original for "which twill. be described hereafter.

21:3 :position. .iIn this form. of control system when the .blowenand.ignition are turned onrand. the fuel valve is opened upon initiation offuel fiow to the burner. the flow responsive switch I84 is operable toclose the contacts M2 and I83 and establish a completed circuitfor therelay coil '15. This energization of the relay coil 75 by the flowswitch l'84isoperable to'deenergize the timer motor and the ignitionaswas previously described and to cause the switch contact arm 56 to belatched downby the latchmember 1?. At this point in the operation: ifflame occurs in the'burner the photocell I lTwill render the electrontube I54 conductivexand permit the energization of the relay -coill49and cause the same to close the switch contacts I43 and 144 to establisha holding circuit'for the relay coil 25 of the switch 50.:I-Ioweveniffiame does not occur in the burner substantiallysimultaneously with the emergence offuel thereinto the flow responsiveswitch I35 will open thecontacts H32 and I83 after theaforementionedmomentary closing and will thus deenergizetherelaycoil land cause the switch structure 65 to. assume. the latched-out or safetyposition previously described. If, for some reason, .the flow switch l84does not function the systemwill operate as doesthe system in Fig. 1withthe exception that the photocell circuit will give a-faster-responseto the occurrence of flame than will the stack switch in the circuit ofFig. 1.

In-the system thus far described it is evident that if the flow switch$34 should not function and flame should not occur in the burner withinthe predetermined time required for the travel of the cam face 34 of theoperating member 32 under the bearing. roller 55 theswitch lever 44 willmove totthe. locked-out safety position as isshown in Fig.6. Similarly,if there is a loss of flame from ayrunning or operating position therelay switch structure 65 will assume the latched-out or safety positionshown in Fig. '7. As was mentioned with regard to-the system of Fig. 1the timer motor, gear engaging means'and switch structure associatedtherewith,.and the relay switchstructure' 60,- as well as thetransformer 53, would probably be encased as a unitary control devicefor commercialconstruction. It should be noted that the control.devicewhich could be manufactured from the parts of this system justmentioned is a basic control device common to those systems of Fig.1 andFig. 13 and can be adapted for use with either a stack'switch or aphotocell circuit or other fiameresponsive means, either with or withoutthe-fiowsresponsive switch without change of the interior circuitstherefor.

In Fig. lithere .is shown a modified burner controlsystem which issomewhat similar to the ones .previously described and in whichqone oftherelay coilshas been eliminated. In this systemthereis a burneri25lwhichis supplied with airbyia bl-ower.202 driven by a motor-203 whichalso :drives a'fuel; pump 254. The fuel pump204isoperable:to;supply'fue1 to the burner nozzle 205 :andithe supplyof'fuelto the nozzle. is controlled ;by aan electrically operated fuelvalve 255,;aswas the system shown in Fig.1. There is also providedelectric ignition 261, the circuits Thereis a'ztransformer 258 :having;a primary 209- and-a secondaryi H) which controls the 'energization ofthis system. The transformer primary 259 is supplied :with electriccurrent from the main power '1 source 2 by conductors .212 and2l3. .Therconductor. 2 [-3 leads to the contact arm .214 and switch .;-co-ntact,i2 [5 which. is initially engaged withranother :conta-ct 2 l E :on aicontact arm :2 l l.

:The :circuit for. the primary is completed .byxcon- .ductor2l8 from thecontact-arm 2|! back to the primary: 209. There is' at: switch means.orswi-tc'h structure generally designatedzasrz I 9 for controlling thevarious circuits in this-systemandwhich includes *afswitch operatinglever '22 0 which is pivoted at-22l and which is operable to bemoved forswitch actuation bya pivot-ed operating member 222. :The switchlever220' carries'on itsopcrating -'-end. .a, "plurality .of': switchoperating. fingers; 223,224..- 225; 226,-and .221,' the fingers 22-5,226 and? 22'! :being of electrica1s conducting-material-andinterconnected for. conduction of :electriecurrent to variouscircuitsherein. There is a flexible contact arm 228 carryinga switch contact229'2andwhich-is arranged for. movement by the finger -.224. The-contact*229-is oooperable withaa-contact 235 which is carried -by aflexible contact anmz 23l and is limited in. its movement by aStQp23L:There is-another. flexible contact arm 233 which vcarries aicontact234z-and which is; limited in: its downward: movement; by a. stop 235.x'Ilhetcontact 23 4.is ..cooperable withia contact 236 which iscarried.by .a 'contactsarm 231 which is arranged for operation by the finger224. There .is "also, provided a-another :contact arm. 2 3 8whichccarries. .a: contactz239 coopera-ble-with the electricalconducting finger 225. Thereiarealso provided contact "arms .--2 4i! and24 I whichzcarry initially. closed :contacts% 242 and 243 ,1 the contactarm 245: being limited in its downward movement by a stop-244. Thecontact arm 24lalsocarries a con-tact 245- which is cooperable with the.electrical1conductingfinger :226. Thezcontact arm 2 l1 also carries-"acontact 246 which. issarranged for engagement with the electrical:conducting finger 221. One siderbfthe transformersec- .ondary (2 0' isconnected by .a' conductor 24'! to thefix-ed'c-ontact 248 of a room:thermostat: generally designated as i249. Thezroom ithermostat 249- isoperable to controlthe energization of this control system in accordancewith .the heat: requirements-cf the space being heated by theburner'20l. This thermostat mayor may not tbe:of the'anticipating typebut is shownas such forthis circuit diagram. The movable contact 2550fthe thermostat=.249 is carried bya bimetallic blade i25l which-isconnected to the othereside ofIthe secondary 2"] by aconductor .252havingt an anticipating heater 253andre- .sistor .254 therein. There .isan electric timer motor 2-55 which is operable to transmit movement-tothe operating-member 2 22 foruoperating the switch structure H9. Themotor 255 has a shaft 256 with a pinion gear 25'! thereon. There is-amember 258 pivoted'onthe shaft 256 for carrying a; pair :of gears 259and 260 thereon. .Theoperating member 222.is pivoted asati26l .andhas:a;cam face at itsaupp-erendgenerally designated as: 252. The:member,:222 has at. its lower fend asector geariportion 263which isco-operable with thegearlfiil. The. member 258 iszoperable to move-the.-gear 265 into and out of en agement withzthe sector. gear 253. Therejisa gear-engaging lever-264 which. is pivoted a :at 255 and-whichhas. aleaf :spring portion 266 '00-- operable withia-pin261 on ansextension268 of the; gear -.eng9;ging member 258. The lever :264has-..-a;.portion 2-6.9 which is operable as a: magnetic .-.armature=and1is -cooperable with .the electromagnet -;210. .Th'e-lever:"2-64 hasan end 'portion 2' *which-is of electrical conducting. material and"which :has 1two.fingers 212 and1213 cooperablewithcontacts- 274 and 215carried. by the flexible .contact arms 7-6 :and 271 respectiveiy. The:contact: arms. 2 lfoiand-Z "H are limited in their downward movement bystops 219 and 219 The contact arms 219 and 211 are connected byconductors 289 and 291't0 the conductors 213 and 218 and provide acircuit for the transformer primary 299 which is in parallel with theswitch contacts 215 and 219. There is a spring 292 which is connected tothe operating member 222 and is operable to hold it in the positionindicated in Fig. 14. A spring 283 interconnects the lever 294 and thelever 229 and is operable to hold the lever 229 in the initial positionindicated in Fig. 14. The blade 251 of the room thermostat 249 isconnected by a conductor 294 to a terminal point 285 at which point thecircuits divide. From the terminal point 235 conductor 2B9 leads to thecontact arm 231, conductor 281 leads to one side of the electromagnet219, and conductor 299 leads to the movable contact 289 of a stackswitch generally indicated as 299. The switch contact arms 231 and 233are connected together as at 291 and a conductor 292 leads from thecontact arm 229 to one side of the timer motor 255. The other'side ofthe timer motor 255 is connected by a con-ductor 293 to the transformersecondary 219. The other side of the electromagnet 219 is connected by aconductor 294 to a point 295 on the conductor 293 from the timer motor255. There is a conductor 296 which connects the fixed contact 291 ofthe stack switch 299 to the conductor 292 which leads to the timer motor255. The contact arm 241 is connected by a conducto 298 to one side ofthe blower motor 293, the other side of which is connected by conductors299 and 399 to the high voltage primary wire 212. The contact arm 249 isconnected by conductor 391 to one side of the primary 392 of theignition transformer 393, the other side of which is connected byconductor 399 to the high voltage wire 212. The ignition transformersecondary 394 is connected by conductors 395 and 399 to the ignitionmeans or electrodes 291. The switch contact arm 233 is connected byconductor 391 to one side of the fuel valve 299, the other side of whichis connected by conductors 398, 299 and 399 to the high voltage wire212. The switch lever 229 has a downturned end portion 399 which carriesa bearing roller 319 against which the cam face 292 moves for operatingthe switch structure 219. There is also provided a stop 311 limiting themovement of the switch operating member 222 and a reset member 312 whichis engageable with the lever 229 for resetting the same.

In operation this system functions generally as follows: When the roomthermostat 249 closes calling for heat circuits are established forenergizing the timer motor 255 and the gear engaging electromagnet 219.These circuits extend from the transformer secondary 219 by way ofconductor 241, contacts 248 and 259, conductors 294 and 299, stackswitch contacts 289 and 291, conductors 299 and 292, to one side of themotor 255. From the terminal point 295 conductor 281 runs to one side ofthe electromagnet 219, the other side of which is connected by conductor294 to the conductor 293 leading from the other side of the motor 255 tothe transformer secondary 2 I 9. There is a parallel circuit forenergization of the timer motor 255 which bypasses the Staci: switch 299and extends from the terminal point 295 by way of conductor 285, switchcontacts 236, 234, 239, and 229, and conductor 292 to the motor 255. Thelast-mentioned circuit for the motor is initially open at contacts 229and 239 as is seen by reference to Fig. 14. Prior to the closing of theroom thermostat contacts the various switches shown are in the positionsas indicated in Fig. 14. When the room thermostat 249 is closed and theelectromagnet 219 and the timer motor 255 energized the gear 299 ismoved into engagement with the sector gear 293 on the switch operatingmember 222 and this member begins to move for operating the switchstructure 219. When the electromagnet 219 moves the lever 294 forengaging the aforementioned gears the end portion 211 is moved to engagethe contact fingers 212 and 213 with the switch contacts 214 and 215 toestablish a holding circuit for the primary 299 of the transformer 299.The cam face 252 of the switch operating member 222 is operable to bemoved by the timer motor 255 under the bearing roller 319 for pivotingthe lever 229 and operating the switch structure 219. The cam face 292is so contoured as to move the lever 229 through sucoessive movements tooperate the various switch contacts sequentially as will be describedhereafter. Upon initial movement of the cam face 292 under the bearingroller 319 the lever 229 is pivoted to engage the finger 223 with thecontact arm 228 and move the contact 229 into engagement with thecontact 239. When the contacts 229 and 239 are in engagement theaforementioned parallel circuit for energizing the motor 255 is closed.The fingers 229 and 221 on the lever 229 are positioned to engage thecontacts 245 and 249 respectively and to break the contact 219 away fromthe contact 215. The establishment of the last-named contacts and thebreaking of the contacts 215 and 219 are operable to open the initialcircuit for the tranformer primary 299 which remains energized throughthe switch contacts 214 and 215 and to establish a circuit for theblower and ignition. The blower and ignition are energized by a highvoltage circuit extending by way of conductor 218, switch contact arm211, contacts 221 and 249, and contacts 225 and 245. From contact 245the circuit splits and goes by way of contact arm 249 and conductor 391to the ignition transformer and by way of contact arm 241 and conductor298 to the blower motor. A short predetermined further movement bringsthe cam face 292 to a slightly higher contour to move the lever 229 asmall distance further necessary to make contact between the finger 225and contact 239 to establish a circuit by way of conductor 391 to thefuel valve 296. By this construction the sequential operation of theblower and ignition and fuel valve is accomplished similarly to thatdescribed for the previous forms of control system. Upon a shortpredetermined further movement of the operating member 222 the cam face252 is moved to a still higher contour which pivots the lever 229further and causes the finger 226 to flex the contact arm 241 and movethe contact 243 away from the contact 242, the contact arm 249 by thistime having engaged the stop 244. Upon opening of the contacts 242 and243 the circuit to the ignition transformer is broken but the circuitsto the blower motor and fuel valve are maintained as their contacts arestill in engagement. Upon a predetermined further movement of theoperating member 222 the cam face 292 is moved to its highest contour atthe extreme right edge thereof and the finger 224 is operable thereby toengage the contact arm 231 and open the contacts 234 and 239. By theopening of the contacts 234 and 236 one of the parallel circuits forenergizing the timer motor 255 is opened and the 1 7 eontrol of this.motor is :at this point entirely determined :by the stack switch :290.The stack switch 290' "has normally closed contacts which are operableto be opened upon occurrence of :fiame in the burnerandso if flame hasoccurred in the burner :by the time the contacts .234 .and

236 are opened vor oecursin the .aburner a. very. short time thereafter:the stack switch contacts flflliand 291mm he cpenedand the timer motor255 deenergized to stop further movement .o-frthe operating member 222.If flame ;does not occur fin-the burner :within. the predetermined..time required .:for the cam face :262 :to move completely under thebearing roller 311:!) the motor-25.5 will continue movement of themember 222:2. until the hearing roller ;3.l:0 drops over the edge of.the member 222. and. pivots the lever 22d upward to open the switcheswhich were previously closed and close the .switches which werepreviously opened thereby and assume a locked-out --posi flan-similar.to that shown in Fig. 16. The elever 210 can. be manually moved by the:reset meme her 312 .to move :theabearing roller,fiitflj-anddownturnedlever portion 399 out .of latchingeneage- .ment-.with.the.joperating member 222 :to permit theqsystem to hereestartedafter a safety operation.' in the. systemajhais started normally andfiame'has occurred inthe :burner the timer motor 2-.55 is stoppedandthe. aforementioned saietv operation d,oes..not;..occurabut,iffor somereason, name rails iromea. running. or operating.:positionthenstackjswitch contacts 12cc. and 257 will reclosezandestablish acircuit :to .start;the timer motor :255 and thus moveithe.-.operating membe 222 through to a safety lock-outrposition. Furthermovement of the operating member 222 after reaching aflock=out position.is prevented byeengagementthereof with the stopmember 31! which;is.o.perable vto stop vfurther movement and thnscstall thamotor 255..

il irom-zthe-ioregoing it is seen that there is pro.- vided .a simpleburner control system whereby the blower, ignition, and .fuel ,supplyare turnedonator:azpredetermined .timeuand theignitionzisethen {turnedpfivall thiszdone by .a timing motor. and switchzstructure associatedtherewith and-inflame: does not .occur "within apredeterminedtimeinitheaburnergtheitiming'motonmowes'ensueinerelectromag-net. .It should also be .noted that, although :a.normally closed thermostatic stacksswitchgis-shown for deenergizingthetimer motor aupon ec'currence-offlame aphotocell eircult-pr any-oth.er;flame response couldv be used whichwvouldgbe satisfactory foropening .a nonmallyplosed .switcl'icontrolling the timer =motor. pi the.two seduentialswitches formed by contact-451,229,130 and contacts234-,.:23G-whic-h are initially ppen. and subseguentlyclose and laterreopen aqnarallel circuit {for the timer motor. the itimer :motor isprevented from operating in theevent;oiia afalsaind cationor a.:flame bythe namemesponsiveaswitch:crrimany event thatithe flamemesponsive switchis 'iheldopen. *It should.

fire-noted by':providing :two circuits forenergizlngithe transformer:primary i209,v one .of Wbich .is initiall'y closed and is opened by thetiiner mo'tbrand'rthe other or v'rhich is initially" 18 open and isclosed by the gear engaging electro' magnet, thesystem is prevented fromfunctioning in the event that the switch operating 'lever 220 is jammeddown in an actuated position.

Having thus described the invention. what is claimed and desired to besecured by Letters Patent of the United States is:

'1. In a burner control system, a burner, electrically controlled meansfor supplying fuel .to said burner, electrical ignition means :for saidburner, circuits for said fuel supply means and said ignition means, afirst switch means 100 .1- trolling energization of said fuel supply:means and said ignition means, operating-means biased in one directionto an initial inoperative :position and operable upon movement in theother direction to close and subsequently to 'reopen said switch means,electrically operated timing'means operable to move said operatingmeansv in said other direction to actuate said firstswitch means,electrically operated releasable means having an actuatedpositionoperable to transmit-movement from said timing'means to saidoperating means, said releasable means being operable upon re lease fromsaid actuated position to :permit said operating meansto return to saidinitialposition to open said firstswitch means, electrimcircuit meanscontrolling energization of said timing. means andsaid'releasable means,a second switch means controlling said ignition means-and said timingmeans, and means responsive to the .occurrence of' fiame in said burnerand controlling said'second-switch meanasaid responsive means and saidsecond switch means being jointly-op..- erable upon occurrence of flamein said burner within a predetermined time after theiclosing of saidfirst switch means to deenergize said timing means and said ignitionmeans to prevent the reopening of said first switch means bysaid ingmeans.

, '2. In a burnercontrol system, -aiburner,..elec.- trica'lly operatedmeans tor supplying fuel :to said burner, "electrical ignition means-{orsaid burner, circuits for 'said fuelsupply means and said ignitionmeans, a first switch means :controlling energization of said fuelsupply means and saidignition means, an operating member biased in onedirection to an initial inoperative positionand operableupon movementinthe other directionito close and subsequently to-reopensaid switchmeans; an electricmotor operable as-atiming means {or moving saidoperating member insaid otherdirection to actuate saidfir st-swi;tch=means, electrically operated releasable means having, an actuatedposition operable to transmitgmovement from said motor ,to said qperatinmember; saidreleasable means being operab'le upon release from saidactuated position 'to' permitsaid operating member to return to; saidinitial position to .open said first switch means, electric circuitmeanscontro n energizationof said motor and said releasable means; a secondswitch-means controllin the eners zati n' of Said ignition means andsaid electric motor, means responsive to the occurrence of fia-merinsaid burner andcontrolling saidsecond'switdh means, and said resppnsivemeansfbeing operable-upon occurrence of gfiame in said burner within-a.-pre-' determined time after'the closing or said first Y switchmeansto .open said second switch meanstrically operated means for supplyingfuel to said burner, electrical ignition means for said burner, circuitsfor said fuel supply means and said ignition means, a first switch meanscontrolling energization of said fuel supply means and said ignitionmeans, an operating member for actuating said switch means, saidoperating member being biased in one direction to an initial inoperativeposition and operable upon movement in the other direction to close andsubsequently to reopen said switch means, an electric motor operable asa timing means for moving said operating member, gear means fortransmitting movement from said motor to said operating member,electrically operated means for effecting an operative engagement ofsaid gear means for transmitting movement to said operating member, saidelectrically operated means being operable upon deenergization torelease said operating member for return to said initial position, aroom thermostat controlling energization of said electric motor and saidelectrically operated means, a second switch means controlling theenergization of said ignition means and said electric motor, meansresponsive to the occurrence of flame in said burner and controllingsaid second switch means, and said responsive means being operable uponoccurrence of flame in said burner within a predetermined time after theclosing of said first switch means to open said second switch means todeenergize said ignition means and said electric motor and thereby toprevent the reopening of said first switch means by said operatingmember.

4. In a burner control system, a burner, electrically operated means forsupplying fuel to said burner, electrical ignition means for saidburner, circuits for said fuel supply means and said ignition means, afirst switch means controlling energization of said fuel supply meansand said ignition means, an operating member for actuating said switchmeans, said operating member being biased in one direction to an initialinoperative position and operable upon movement in the other directionto close and subsequently to reopen said switch means, an electric motoroperable as a timing means for moving said operating member, gear meansfor transmittin movement from said motor to said operating member andhaving portions one of which is movable into and out of engagement withthe other, electromagneticmeans for moving said one portion intoengagement for transmitting movement, saidelectromagnetic means beingoperable upon deenergization to, release said operating member forreturn to said initial position, a room thermostat controllingenergization of said electric motor and said electromagnetic means, asecond switch'means controlling the energization of said ignition meansand said electric motor, means responsive to the occurrence of flameinsaid burner and controlling said second switch means, and saidresponsive means being operable upon occurrence of flame in said burnerwithin a predetermined time after the closin of said first switch meansto open said second switch means to deenergize said ignition means andsaid electric motor and thereby to prevent the reopening of said firstswitch means by said operating member.

5. In a burner control system, a burner, electrically operated means forsupplying fuel to said burner, electrical ignition means for saidburner, circuits for said fuel supply means and said ignition means, afirst switch means conerated means, a spring connected to said operatingmember for returning the same to its initial 3 starting position upondeenergization and release of said electrically operated means, a secondswitch means controlling the energization of said ignition means andsaid electric motor, means responsive to the occurrence of flame in saidburner and controlling said second switch means, said responsive meansbeing operable upon occurrence of flame in said burner within a predetermined time after the closing of said first switch means to opensaid second switch means to deenergize said ignition means andsaid-electric motor and thereby to prevent the reopening of said firstswitch means by said operating member, and means operable in the eventof reopening of said first switch means by continued movement of saidoperating member to hold said operating member in an actuated positionindependently of and subsequent to deenergization of said electricallyoperated means by sai room thermostat. 6. In a burner control system, aburner, electrically operated means for supplying fuel to said burner,electrical ignition means for said burner,

gization of said fuel supply means and said ignition means and includinga contact making lever, said switch lever having a downwardly projectingbearing portion, an operating member operable upon initial movement toengage said lever' pro;- jecting portion to move said lever to closesaid switch means and upon continued movementto reopen said switchmeans, an electric motor opergable as a timing means for moving saidoperating member, gear means for transmitting movement from said motorto said operating member and having portions one of which is movableinto and out of engagement with the other, an operating lever having amagnetic armature portion and operable upon movement to move said onegear portion into engagement with the other, an elec tromagnet operableupon energization to attract said armature portion and move said lever,a room thermostat controlling energization of said motor and saidelectromagnet, a spring connected to said operating member for returningthe same to its initial starting position upon deenergization' of saidelectromagnet, a second switch means controlling the energization ofsaid ignition means and said motor, means responsive to the occurrenceof flame in said burner and controlling said second switch means, saidresponsive means being operable upon occurrence of flame in said burnerwithin a predetermined time after the closing of said first switch meansto open said second switch means to deenergize said ignition beingoperable in the event of failureof

